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  • systemd management using systemctl and journalctl to check systemd logs


    systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system. The key commands or arguments you will use with systemctl are the following: Unit Commands:   list-units [PATTERN...]         List loaded units &nbs........
  • VMWare ESXi 6.7 SSH/PowerShell CLI Commands


    [root@localhost:~] BootModuleConfig.sh          echo                         host-ind                     nfcd                   ........
  • Linux How To Clone One System Harddrive to another remote system


    The easiest way is to use SSH and DD or a combination of netcat.  SSH will be a little slower due to encryption but is the most secure way (on two older systems the average clone speed is about 40-50MB/s).  This is also OS independent as it doesn't matter what the source OS is because you are literallly cloning the drive so you retain the partition table and settings.   Clone HDD using SSH and DD........
  • Ubuntu/Debian/Linux won't boot and drops to Busybox shell after cloning HDD with dd


    I don't recall having this issue in the distant past but nowadays at least Debian seems to be very picky about this. I used dd to copy one hard drive to another and tried booting it.  Everything seemed fine with grub working but each time it would drop to the busybox shell.  There is no particular error so this is misleading. Normally the first things you would check are to make sure your fstab is correct (that the UUID is correct) and that you've updated grub.&........
  • USB Device/MP3 Player not working properly and can't browse the device filesystem? Check the cable twice and again!


    Here is a simple MP3 player and now there's a reason to understand why the supplied cable has some kind of capacitor and is very short.  These devices can be VERY finicky and any voltage fluctuation or difference is enough to cause issues.   Take for example the error messages from Linux Mint: [804829.895414] usb 1-1: USB disconnect, device number 11 [806961.109030] usb 1-1: new high-speed USB device number 12 using xhci_hcd........
  • Errors were found while checking the disk drive for /.


    I will start by saying I think I know what caused this boot-time error on Linux Mint but should also apply to Debian and Ubuntu. I changed my BIOS time to several hours in the past to match the current time, but this caused Linux to think there were incorrect filesystem times.  The problem is that it seems when you hit this I am not sure what is happening, it doesn't seem to be doing fsck and hangs without prompting the user.  What I have found is that........
  • Howto Convert Xen Image to KVM


    #count=10000 makes an image of 10000MB make sure your image is at least the same as your existing dd if=/dev/zero of=yourimage.img bs=1M count=10000 # losetup -fv newimage.raw # fdisk -cu /dev/loop0 # kpartx -a /dev/loop0 # dd if=<xenimage> of=/dev/mapper/loop0p1 # e2fsck -f /dev/mapper/loop0p1 # resize2fs /dev/mapper/loop0p1 # a lot of guides tell you to edit /etc/fst........
  • init: tty (/dev/tty2) main process (1031) terminated with status 1 init: tty (/dev/tty2) main process ended, respawning


    After some fsck issues I can't boot my Centos 6.4, this just keeps repeating over and over. init: tty (/dev/tty2) main process (1031) terminated with status 1 init: tty (/dev/tty2) main process ended, respawning Disabling SELinux through Single User mode fixed this.........
  • Samsung Galaxy Note Upgrade to ICS 4.0 microSDHC card not detected/dataloss after upgrading - possible solutions


    I backed up everything in the /mnt/sd_card directory thinking that some dataloss could occur for some reason but purposely left my microSDHC unbacked up thinking that "it won't touch that since it's external" and Samsung's and other manufacturers website even say this (that it won't be affected and not to worry etc). Apparently I was wrong, my microSD was "undetected" and asked to be formatted after the upgrade (there goes 3-months worth of family photos).  No........
  • xen how to resize an image properly


    The best way I could figure out is to use another guest of some sort to do this, while assigning the disk that needs to be resized to the same guest. So say we have /dev/xvda as the guests drive and we've booted it up. We also have /dev/xvdb (this is going to be the image/disk to be resized). In this case it's based on an ext3/4 image. Run e2fsck on it to ensure there are no filesystem errors. e2fsck /dev/xvdb........
  • Xen how to mount disk images off-line and access data


    fdisk -lu VPS.img last_lba(): I don't know how to handle files with mode 81ed You must set cylinders. You can do this from the extra functions menu. Disk VPS.img: 0 MB, 0 bytes 255 heads, 63 sectors/track, 0 cylinders, total 0 sectors Units = sectors of 1 * 512 = 512 bytes      Device Boot      Start         End   ........
  • mdadm RAID 1 adventures


    I separated the 2 drives in the RAID 1 array. 1 is the old one /dev/sda and is out of date, while the separated other one /dev/sdc was in another drive and mounted and used with more data (updated). I wonder how mdadm will handle this: usb-storage: device scan complete md: md127 stopped. md: bind<sda3> md: md127: raid array is not clean -- starting background reconstruction raid1: raid set md127 active with 1 out of 2 m........
  • mdadm won't boot due to fsck error


    Nov 29 20:17:58 ubuntu kernel: [ 1157.180789] md: md1 stopped. Nov 29 20:17:58 ubuntu kernel: [ 1157.180829]  md0: unknown partition table filesystem not responding/reading properly with du or rsync (this needed an fsck). [ 2571.489217] EXT3-fs error (device md2): ext3_lookup: deleted inode referenced: 35923106 [ 2571.942299] EXT3-fs error (device md2): ext3_lookup: deleted inode referenced: 35923110 [ 2571.9568........
  • GRUB "Error 2: Bad file or directory type" 0.97 won


    You can see the problem below, GRUB recognizes my hard drive and sees the partitions but cannot access them.  This is from the GRUB boot disc I'm using. What happened is that I had some power issues causing this system's power to be interrupted several times and basically an on/off on/off situation. The system won't boot, I just get a flashing cursor and no message or error from GRUB.  Obviously the problem is that my MBR seems corrupt or some other issue. My........
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